Container closure construction



C. T. DRAPER CONTAINER CLOSURE CONSTRUCTION Dec. 21, 1943- Filed A ril 22, 19:59 2 Sheets-Sheet 1 //VVWTOA.'

Cf/A/PZIS Z'fl/MPER v Y rranwtf v Patented Dec. 21, 1943 CONTAINER CLOSURE CONSTRUCTION Charles T. Draper, Cleveland Heights, Ohio, as-

signor, by mesne assignments, to American Flange & Manufacturing 00., Inc., New York, N. Y.. a corporation of Illinois Application April 22, 1939, Serial No. 269,545

2 Claims.

The invention relates to bung opening constructions for metallic containers, barrels, drums, vessels, packages and the like, utilized for shipping, storing and/or dispensing fluid, liquid, or semi-solid materials; and relates more particularly to a simplified threaded bung openin plug and theft sealed closure construction.

Moreover, this application is a continuation-inpart of my copending application, Serial No. 181,875, filed December 27, 1937, now matured into Patent No. 2,156,237; and Serial No. 207,285, filed May 11, 1938.

Metallic containers are extensively used for transporting, storing and dispensing various kinds of lubricating oils and the like, and such containers are usually provided with means for preventing undetectable tampering with the closure structure.

Accordingly, metallic containers heretofore have been provided with threaded bung rings within which threaded plugs are secured; and the bung ring and/or plug is preferably provided with means for preventing undetected access to the container.

Moreover, it is desirable that the bung opening and closure structure be such that complete or substantially complete drainage of the container may be effected through the bung opening.

Accordingly, metallic containers heretofore have been provided almost universally with cast, forged, or specially pressed bung rings or bushings having internal threads; the bung rings being secured in liquid-tight manner by seaming, welding or the like to the container wall; the bung rings or plugs threaded thereinto providing for the securement of the means for preventing undetectable access to the container; and the bung rings being arranged to project wholly outwardly of the container wall in case complete container drainage is desired.

In many cases, special types of closure plugs are required for use with particular bung rings and tamper sealing means; and two or more gaskets are frequently required or used, interposed between the container wall, bung ring, plug, and tamper seal, in order to assure a liquid-tight closure.

Moreover, threaded plugs heretofore have been made of cast iron, drop forged or pressed steel, and have also been die cast; and excepting in the case of a die cast threaded plug, standard pipe threads have been cut by usual methods in the cast, forged or pressed bung rings or plugs.

The manufacture of such threaded plugs and bung rings involves the use of a considerable amount of metal if they are made of cast iron or drop forgings, and involves the use of very expensive metal if they are die cast.

Moreover, the cutting of threads in a cast iron, drop forged or pressed metal plug or bung ring is a relatively expensive operation. Likewise, the securing of the bung rings to the container wall, the manufacture and sealing of the tamper sealing means, and the provision of the gaskets are each relatively expensive operations.

Thus, the composite expense involved, due to the amount or character of metal used and the threading thereof, greatly increases the cost of manufacturing metal containers so that the cumulative expense of most or all of the enumerated parts or operations forms a relatively large portion of the total cost of manufacturing sheet metal containers in accordance with prior practice.

It is therefore a primary object of the present invention to appreciably reduce the cost of manufacturing metallic containers by greatly reducing the prior disproportionate cost of providing the bung opening, plug and appurtenances; Without, however, sacrificing complete container drainage, a liquid-tight construction, or adaptability for the reception of tamper sealing means.

A further object of the present invention is to provide a container bung opening construction having roller swaged threads with which a threaded closure plug of any one of a variety of forms may be readily secured with the use of only one gasket, and without utilizing any separate, specially cast, forged or machined threaded bung ring or the like; which bung opening construction is peculiarly adapted for the ready and easy reception of tamper sealing means, and which bung opening construction provides special advantages when closed by a sheet metal plug similarly formed with roller swaged threads.

The threads in threaded bung openings of metallic containers are usually formed as standard pipe threads because the bung openings must be adapted for the reception of standard pipe threaded fittings; and the closure plugs therefor must necessarily be provided with standard pipe threads which have a particular pitch for any particular size of opening and which also have a V-sided or V-shaped thread form with the angle of the V being degrees.

Metallic containers are usually made from sheet, strip or plate metal of from 24 to as heavy as 12 gauge material, and ordinarily the thickness of the metal in the bung opening or the plug need not be substantially greater than that of the container wall if made of the same metal, except that prior practice requires much thicker plug and bung ring metal in order to allow for the cutting of the pipe threads therein.

Most of the metallic containers now used, to which the present invention pertains particularly, are made from 18 gauge sheet or strip metal and the threaded openings therein frequently range from inch to 2 inches in diameter. It would obviously be impossible, in accordance with prior practice, to cut standard pipe threads in a bung ring or plug for a /4 inchto a 2 inch opening, if the ring or plug is formed from sheet metal of about 18 gauge.

Rounded corrugated-like threads having a pitch of from 4 to 6 threads per inch similar to the threads on fruit jars, have been made in very thin sheet metal by a stretching operation, but such threads do not have the accuracy, pitch or V-s'ides which characterize standard pipe threads and will not receive a standard pipe threaded fitting.

For more than sixty years during which I have had experience in the art of making sheet metal containers of all sorts, sizes, kinds and shapes, I have never seen an integral neck in a sheet metal container provided with standard pipe threads in which the threads had not been formed by cutting; I have likewise never seen an integral threaded neck eccentrically located in a container wallin which said threads had 'not been formed by cutting; I have likewise never seen a sheet metal plug provided with standard pipe threads in an annular wall thereof in which the threads had not been formed by cutting; I have likewise never seen an integral neck in a sheet metal container adapted for securing tamper sealing means thereunto, which I neck is provided with standard pipe threads, in

ting.

Accordingly, it is a fundamental object of the present invention to provide a 24'to 12 gauge rolled steel container wall with an integral bung opening neck having standard pipe threads formed therein without cutting the threads, and toprovide a threaded sheet metal plug made from 24. to 12 gauge rolled steel with a standard pipe thread formation without cutting the threads.

Moreover, it is an object of the" present invention to provide a sheet metal container with an integral bung opening neck having V-sided internal and external threads, and to provide a sheet metal plug having an annular wall provided with internal and external \f-sided threads; the said internal and external neck and plug wall threads having an accurate, definite, rolled or swaged V,-shape or form with relatively sharp or pointed valleys andwith substantially sharp or slightly rounded crests or apices.

Moreover, it is an object of the present invention to provide a container closure structure including a sheet metal bung opening neck and/or a sheet metal plug having an internally andexternally threaded annular wall, the metal inthe annular wall being swaged, deformed, cold rolled, ironed, burnished, spun, flowed, smoothed and hardened as by working between roller dies "thread apices may be said to be compressed thread apices as distinguished from the stretched, thinned thread apices of threads formed by bending or distorting metal under tension by a stretching. operation, as results when the prior rounded, corrugated-like threads, similar to those on fruit jars, are made in sheet metal.

Moreover, it is an object of the present invention to provide a threaded sheet steel closure structure including a threaded bung "opening neck and a threaded plug each provided with standard pipe threads, which pipe threads have cold rolled, smoothed, ironed or burnished, hardened surfaces, as distinguished from threaded surfaces formed by cutting which have chatter marks and scoring; so that when the threaded sheet steel plug is engaged in the threaded sheet steel bung opening neck, no seizing of metal to metal occurs, which is ordinarily the case when two steel threaded members are engaged.

It is a further object of the present invention to provide a sheet metal container wall with an outwardly projecting sheet metal bung opening neck terminating in outturned sheet metal flange means and having an inner and outer pipe thread formation in the neck between the wall and flange means; and to provide a sheet metal plug for the bung opening with a closing wall terminating in a projecting annular wall, which terminates in an outturned flange and having an inner and outer pipe thread formation in the annular wall between the closing wall and flange; whereby the neck flange means and plug flange may have liquid sealing gasket means interposed therebetween, and whereby the neck flange means and plug flange may be engaged with tamper sealing means.

Moreover, it is an object of the present invention to provide a sheet metal container closure construction including a reinforced sheet metal bung opening neck having standard pipe threads formed therein without cutting the threads, the neck reinforcement providing a flange extending means for an integral flange on the neck, so that the neck and neck reinforcement flange means cooperate with the flange of a, closure plug threaded into the neck for seating liquid sealing gasket means and for receiving tamper sealing means.

Moreover, it is an object of the present invention to provide a sheet metal container with a sheet metal bung opening neck or a sheet metal plug, either or both of which terminate in an outturned flange having threads formed therein so shaped and constructed as to lend a slight axial resilience to the neck or plug to provide a nut-lock action when a plug is threaded into the neck and seated against the neck flange.

Likewise, it is an object of the present invention to provide a. sheet metal container wall with an outwardly projecting sheet metal bung opening neck, and a. sheet metal plug for the neck having an annular wall, the bung opening neck and plug wall each preferably terminating in a flange and each having complementary internal and external V-sided threads formed therein without cutting, one of which is a standard pipe thread, and the threads in the plug and neck being displaced from the tubular locus of the unthreaded parts of the same toward the standard threaded side thereof.

Moreover, it is an object of the present invention to provide a threaded sheet metal container bung opening construction and a threaded sheet metal plug, each having characteristics described in one or more of the preceding objects; each of which may be connected with any standard pipe threaded object; and which when used conjointly have special advantages including the establishment of a steel to steel threaded connection without seizing.

Also, it is an object of the present invention to provide a threaded sheet metal structure, plug or bung opening construction having characteristics defined in one or more of the above objects, to which a tamper-proof seal may be readily applied.

And finally, it is an object of the present invention to provide a container bung opening and closure construction and a threaded sheet metal closure plug and the like, which accomplish the aforesaid desiderata, which opening and plug are greatly simplified in construction and materially reduced in cost; and which provide a most efficient and inexpensive container closure construction.

These and other objects may be obtained by the combinations and constructions constituting the present invention, preferred embodiments of which are shown in the accompany drawings and are hereinafter claimed and described in detail, which may be stated in general terms as including in metallic container closure construction a wall provided with a tubular sheet metal neck, preferably integral of the wall, forming a bung opening for the container projecting or extending preferably outwardly of the container from the wall, the neck terminating in an integral outturned annularfiange or lip, or being surrounded by a ring having an outturned flange forming outturned flange means for the neck, the neck between the wall and flange being provided with complementar internal and external V-sided threads one of which is a standard pipe thread. the metal of the threaded part of the neck wall being internally, externally and throughout its entire thickness roller swaged, deformed, cold rolled, ironed, burnished, spun, flowed, smoothed and hardened into zig-zag thread-like formation with compressed internal and external thread apices, the threads being displaced from the tubular locus of the unthreaded part of the neck toward the standard threaded side thereof, a standard pipe threaded member in threaded connection with the threaded neck to form a closure therefor, said closure member preferably comprising a sheet metal plug having a closin wall provided with an integral annular neck preferably terminating in an outturned annular flange or lip, the plug neck between the closing wall and flange being provided with complementary internal and external V-sided threads one of which is a standard pipe thread, the metal of the threaded part of the plug wall being internally, externally and throughout its entire thickness roller swaged, deformed, cold rolled, ironed, burnished, spun, flowed, smoothed and hardened into zig-zag thread-like formation with compressed internal and external thread apices, the plug threads being displaced from the tubular locus of the unthreaded part of the plug wall toward the standard threaded side thereof, a single gasket interposed and seated between the neck flange means and closure member for sealing the opening in a liquid-tight manner, and a tamper-proof cap enclosing the outer end of the threaded closure member and engaged around and under the neck flange means.

Several embodiments of the present improvements are shown in the accompanying drawings, in which Figure 1 is a side elevation, parts being broken away and in section, illustrating a sheet metal container to which the improvements of the present invention are applied;

Fig. 2 is a plan View with parts broken away, showing one form of improved container closure construction;

Fig. 3 is a vertical section taken on the line 33, Fig. 2;

Fig. 4 is an enlarged view showing the rolled, swaged, or deformed V-thread formation of the integral bung opening construction illustrated in Fig. 3;

Fig. 5 is a view similar to Fig. 3, showing a modified form of construction without a reinforcing collar;

Fig. 6 is a view similar to Fig. 3, showing another modified form of the construction;

Fig. '7 is a View similar to Fig. 3, showing a different type closure plug screwed into the integral threaded bung opening neck;

Fig. 8 is a View similar to Fig. 3, showing a still further modification;

Fig. 9 is a vertical section showing an improved threaded sheet metal plug;

Fig. 10 is a View similar to Fig. 2 showing a modified form of closure construction utilizing the improved plug shown in Fig. 9;

Fig. 11 is a vertical section taken on the line |l-l I, Fig. 10; and

Fig. 12 is an enlarged view showing the rolled, swaged or deformed V-sided standard pipe thread formations of the parts of the closure construction illustrated in Fig. 11.

Similar numerals refer to similar parts throughout the various figures in the drawings.

Referring first to Figure 1, a sheet metal container is generally indicated at 3 and is provided with an improved closure construction at four different places, generally indicated by the numerals M, Ma, Mb and I40. The bung openings for the closure constructions indicated at M, Ma and Mb are shown as being bung openings formed with standard 2 inch pipe threads, while the bung opening of closure construction I40 is a bung opening formed with standard inch pipe threads. Ordinarily only two bung openings are formed in a container, either both in the head, or one in the head and one in the side, at one of the locations indicated in Fig. 1. However, if desired, any number of bung openi ings can be provided in the container, as indicated in Fig. 1.

Referring more particularly to Figs. 2, 3 and 4, the improved bung opening ht is shown therein on larger scales than in Fig. 1. .A container head or top wall 13a may be formed from 24 to 12 gauge rolled sheet or strip steel, and the integral threaded tubular neck projects outwardly of the container and terminates preferably in an outturned annular flange or lip It to form a bung opening for the container. The outturned flange l6 'isformed from the parent metal l3a from which the flange is integrally drawnf and the threads of the integral neck I have a special shape, all of which characterize the present invention. 1 Referring more particularly to Fig. 4,. the threaded neck I5 is provided with standard pipe threads; and the bung opening [4 being a 2 inch threaded opening, the pitch of the threads is 11 threads per inch. If thebung opening werea inch threaded opening, as indicated at Me in Fig. .1, there would Vibe 14 threads per inch. From 3 to 6 threads may be formed in the integral threaded neck [5, five complete threads being indicated in Fig; 4. The. internal thread formation in the neck l5-is such thatthe threads l5a have V-sides I5b, rounded .crests 15c, and relatively sharp or pointed valleys l5d. Similarly, the outer thread formation is such that the threads have rounded crests I50, V-sides [5b, and relatively sharp valleys l5d; and as is more clearly shown in Fig. 1, both the internal and external thread valleys l5d are void.

Moreover, the threaded part of the neck wall is internally, externally and throughout its en-- tire thickness roller swaged, deformed, cold rolled, ironed, burnished, spun, fiowed, smoothed and hardened into zig-zag thread-like formation to provide the threads l5a, without any cutting or shearing or stretching of the metal under tension, as the threaded part of the neck wall is worked under pressure between roller dies in a manner to be presently described.

The deformed or swaged thread formation may be characterized by the thicker metal when measured radially between an outer valley led and an inner crest I50 as shown at H, which is thicker than the metal when measured perpendicularly of a common thread wall between inner and outer V-sides l5b, as shown at l8.

Again referring to Fig. 4, the threads [5a project or are disposed inwardly of the neck indicated at l5; and it is obvious from an inspection of Fig. 3, that standard pipe threads, such as shown therein, could not be provided in metal of the gauge shown at I3a by'cutting threads by the usual tapping operation.

Obviously, if it is desired that the flange 16 be inturned, rather than outturned as shown, the threads l5a would be disposed outwardly of the neck; and in case the flange I6 is not used, there is a threadedformation available on the inner and outer peripheries of the neck, either of which may be sized to a desired standard pipe thread formation.

As shown in the drawings, the internal thread crests, ridges or apices l5c are opposite the external thread valleys I511; and the external thread crests, ridges or apices 150 are opposite the internal thread valleys l5d, so that the internal and external threads are complementary.

Likewise, in Fig. 4, the intern-a1 threads 15a are standard pipe threads and these threads are disposed or displaced inward of the parent neck metalwhich is in the tubular locus of the remaining unthreaded part of the neck. Thus, the threads in the neck are displaced from the tubular locus of the unthreaded part of the neck toward the standard threaded side of the neck.

Moreover, the thread formations in being standard pipe threads, may receive a usual closure plug 20 provided with standard pipe threads, or may receive a standard pipe threaded fitting, which may be attached to the container upon removal .of the closure plug 20. 1

A standard pipe thread such as is referred to herein, is one having V-sides each inclined at an angle of thirty degrees (30) from a plane normal to the axis of the thread, as indicated in page 663 of the first edition (1916) of Marks Mechanical Engineers Handbook.

Additionally, the thread formation is stiff and strong, due to the hardening and toughening of the metal resulting from the swaged formation of the same. This feature distinguishes the threads from the rounded or corrugated-like formation of round threads previously known in the art having a pitch of only from four to. six threads per inch, which will not receive a standard pipe threaded closure plug or coupling.

The integral threaded necks I5 may be provided in a wall of a sheet metal container formed from rolled steel by first drawing a neck at the desired location in a sheet metal blank and by then forming the internal and external threads in the neck by a swaging operation between roller dies, in apparatus shown in my Patent No. 2,145,- 587; and the threaded neck may also be formed by carrying out the method set forth in my copending application for Method of making bung openings, filed December 16, 1938, Serial No. 246,119.

The swaging pressure to which the neck metal is subjected in forming the threads between the roller dies, deforms, flows, or swages the metal of the threaded part of the neck wall internally, externally and throughout its entire thickness into a zig-zag thread-like shape or formation; and the swaging pressure deforms or flows the metal under pressure toform the thread apices I50 so that the internal and external thread apces may be said to be compressed thread apices as distinguished from the stretched thinned .apices of threads formed by bending or distortimproved bung opening is closed by a closure plug 20, only one sealing means or gasket 2| is required, which is interposed between the lower side of the plug flange and the upper side of the neck flange. The neck may be reinforced by an annular ring 22 telescoped around the neck and clamped to the wall [3a by the flange I6 when the flange I6 is formed, This reinforcing ring 22 forms an abutment between the flange l6 and Wall l3a sons to prevent the thin metal neck from being damaged under severe usage.

A tamper-proof sealing cap 23 is placed over plug 20 and has its downwardly extending rim 24 turned inward at 25 by. a suitable tool to engage under the neck flange [6 for sealing the closure against unauthorized opening.

The same threaded neck is shown in Fig. 5'

as is shown in Fig. 3, excepting that the reinforcing ring has been omitted, since in some cases it is unnecessary to provide the same.

The structure of Fig. 6 again is identical with that of Fig. 5, excepting that a different type of closure plug 20a and cap 23a is used.

Referring to Fig. 7, another standard form of closure plug is shown at 201) utilizing a special liquid sealing gasket 2la, which seats within the upper neck opening against the top of the neck threads at the flanged end of the neck. Otherwise the construction is the same in Fig. '7 as that shown in Fig. 3, excepting for the modified form of flange Ifia, reinforcing ring 22a and tamper sealing cap indicated at 231).

Fig. 8 shows a construction similar to Fig. 3,

excepting for the modified form of reinforcing collar 22b and sealing cap 230. In .this construction, the reinforcing ring 2211 is provided with an upper outwardly projecting flange 25 which extends the'flange it of the neck outward somewhat, not only to give a larger surface against which the inturned edge of the sealing cap may be engaged, but also to form a shoulder against which the sealing gasket 2! bites when the plug is screwed into the opening.

Figs. 9, and 12 show a hung opening construction similar to Fig. 8, excepting that the reinforcing ring 220 is formed at its upper end like ring 221), but at its lower end like rings 22 and 22a. Moreover, in the closure construction illustrated in Figs. 10, 11 and 12, the sheet metal closure plug 290 used, incorporates the same improved thread construction that is incorporated in the improved threaded sheet metal neck 15, best illustrated in Figs. 9 and 12.

The improved threaded sheet metal closure plug 280 has a closing wall 28, which terminates in an integral annular wall or tubular projecting or peripheral neck 29 in which standard V-sided pipe threads, generally indicated at are formed; and the neck 22 terminates in an integral outturned preferably circular 3!. The plug Zllc is provided with any suitable wrench or finger engaging means, as by spot welding the ears 32 of a sheet metal U-bar 33 to the closing wall 28; and the U-b-ar 53 may be internally reinforced by bar B l. Thus, the member 33 may be engaged by a wrench or other tool for screwing or unscrewing the plug 2t or into or out of a threaded bung opening.

The improved plug 22c may be made from a cup-shaped sheet metal blank which is threaded by a roller swaging operation on apparatus or by methods disclosed in my Patent No. 2,145,587, or my copending applications, Serial Nos. 207,285 and 246,911, to provide the V-sided pipe threads 39 therein or" identical character to the threads of the threaded neck it.

Thus, the plug 29 between the closing Wall 23 and flange 3!, is provided with complementary internal and external V-sided threads, one of which is a standard pipe thread, the metal of the threaded part of the plug wall at so being internally, externally and throughout its entire thickness roller swaged, deformed, cold rolled, ironed, burnished, spun, flowed, smoothed and hardened into zig-zag thread-like formation with compressed internal and external thread apices. The plug threads also are displaced from the tubular locus of the unthreaded part of the plug wall toward the standard threaded side thereof, which in the case of the plug shown, is the exterior of the plug.

Referring more particularly to Fig. 12, the valleys of both the internal and external threads of the plug are sharp, as shown at 35, and the thread ridges, particularly the outer thread ridges 35, may be sharp or preferably are provided with a very slight fillet or rounded contour. The presonce or absence of the fillet or rounded ridge and the degree of rounding if present, is controlled by the pressure applied between the roller swaging dies during the swaging operation and by the duration of the swaging operation. Likewise, the pressure and duration of the swaging operation control the external diameter of the threaded plug.

When the plug 25c is threaded into the improved threaded neck is, a liquid-tight seal is made by sealing gasket 2! engaged between plug flange 3i and the shouldered flange means 26- 27 at the end of neck l5. Tamper-proof sealing cap 23 is then secured in place having its downwardly extending rim 24 turned inward at 25 by a suitable tool to engage around and under the shouldered neck flange means.

I have discovered that when the improved threaded sheet metal plug 280 is threaded into the improved threaded sheet metal neck IS, the engaged, smoothed and burnished, cold rolled threaded surlaces do not seize even though both parts are of steel.

Moreover, in of the improved closure constructions illustrated in the drawings, the joint between the plug and container is rendered liquid-tight by the use of only one liquid sealing gasket, which is seated between a plug flange and the flanged end of the neck.

Likewise, as shown in Figs. 3, 5, 6, 8, 11 and 12, the outwardly projecting flange means at the end of the neck, whether it be merely an integral flange, as shown in Figs. 3, 5 and 6, or an integral flange extended by a flange on the reinforcing member which is clamped to the container wall by the integral neck flange, in each case constitutes sheet metal flange means, which because of being sheet metal may be extended outward a sufficient distance to permit the tamper sealing cap to be engaged under the flange means by an extended inturned portion 25 while leaving plenty of room beyond the annular portion of the neck wall or reinforcing member therearound to permit the use of any suitable tool for turning the cap skirt inward at 25.

The improved plug 2 0, in having the zig-zag threaded wall formation similar to the zig-zag threaded neck formation, also provides a slight axial resilience in the plug threads which may also give a slight nut-lock action in threading the plug into the opening.

Accordingly, the present improvements appreciably reduce the cost of providing closure constructions for metallic containers and therefore appreciably reduce the cost of such metallic containers; provides an integral threaded bung opening neck without cut threads into which a closure plug having a standard pipe thread thereon may be screwed and the opening sealed in a liqind-tight manner with the use of only one gasket; provides an outwardly projecting bung opening enabling complete container drainage;- provides closure plugs made from sheet metal with standard pipe threads without cutting the threads; provides for the threading of a threaded steel plug in a threaded steel neck without seizing; and provides a structure which may be readily sealed without difiiculty in a tamperproof manner.

In the foregoing description, certain terms have been used for brevity, clearness and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art; because such words in being used for descriptive purposes and not for the purpose of limitation, are intended to be broadly construed.

Moreover, the invention is not limited to the exact structures shown herein, because the sizes of the various parts may be varied to provide other structural embodiments without departing from the scope of the present invention.

The words sheet metal used herein and in the claims are intended to include sheet, strip or plate metal or tube stock having a wall of sheet metal thickness, any of which have the desired and necessary gauge, and may include steel, or other metals from which it may be desired to construct metallic containers or closures therefor; the words standard pipe threads are intended to refer to the various standard pipe threads which are standard in various countries of the world, all of which threads have V-sides; the words "flange means are intended to include a flange on the end of either the bung ring or plug formed as a unit structure, whether the flange is made of one or two pieces, as long as the same is formed from sheet metal; and the words shouldered flange are intended to include a flange on the end of either the bung ring or plug formed with a shoulder, whether said flange is made of one or two pieces, as long as the same is formed from sheet metal.

Having now described the features of the invention, the construction, manufacture and use of preferred forms of the same, and the advantages and results obtained by the improved constructions; the new and useful combinations, constructions and devices and reasonable mechanical equivalents thereof obvious to those skilled in the art, are set forth in the appended claims.

I claim: V

1'. In metallic container construction, a wall provided with a standard pipe threaded tubular sheet metal neck, the neck terminating in an outturned flange, a ringsurrounding said neck and having an outturned flange engaged by and extending said neck flange and forming with said neck flange a shoulder, a sheet metal closure plug having a standard pipe threaded tubular portion threaded into said neck and having a flange in liquid sealing abutment with said shouldered flange, and threaded sheet metal tubular portions of said neck and plug being internally and externally roller swaged throughout.

2. In metallic container construction, a sheet metal wall provided with an outwardly projecting sheet metal bung opening neck, a sheet metal plug for the neck having an annular wall, the bung opening neck and plug wall each terminating in an outturned flange and each having complementary internal and external V-sided threads having rounded apices and relatively sharp valleys, the metal of the threaded part of said neck and plug walls being internally, externally and throughout its entire thickness roller swaged into zig-zag thread-like formations, the threads in the neck and plug walls being displaced from the tubular locus of the unthreaded parts thereof toward one another for threaded engagement therebetween, liquid sealing gasket means interposed between the sheet metal plug and neck flanges, and tamper sealing means engaged over, around and under said flanges.

CHARLES T. DRAPER. 

